1. Field of the Invention
The present invention relates to a cell and, more particularly, to the improvement of the separator of a cell which uses an electrolyte.
2. Description of the Prior Art
As the typical method of producing a coin-shaped cell which uses a tubular three-layered cell element, a method is known which consists of the steps of: placing a mixture for separator between a powder mixture for positive electrode which contains a positive active material and a powder mixture for negative electrode which contains a negative active material, molding them under pressure to obtain a tabular three-layered cell element consisting of a positive electrode/ a separator/ a negative electrode, putting the cell element into a coin-shaped container with a collector welded thereto, supplying an electrolyte in the cell element and then sealing the container (U.S. Pat. No. 4,782,548). In this case, when the electrolyte is supplied to the tabular three-layered cell element, the positive electrode, the separator and the negative electrode exhibit a volume increase of substantially the same degree.
Such a conventional method of producing a cell, however, is disadvantageous in that when three-layered tablets are continuously manufactured by the same die, a stain of the die adheres to the outer periphery of the three-layered tablet, which is apt to cause short circuit, and in that when short circuit is generated, the supply of the electrolyte causes internal short circuit, which leads to the drop of voltage and reduction in capacity. To prevent such trouble, it is necessary to frequently clean the die.
The present invention has been made in order to eliminate the above-described problems in the prior art.